Field
The described technology generally relates to a probe system for an aircraft.
Description of the Related Art
In aeronautics, the piloting of an aircraft is based on the knowledge of the primary references thereof. These references comprise, inter alia, its speed relative to the ambient air, its altitude and its angle of attack.
These references are determined using probes situated on the cockpit of the aircraft. These probes may comprise pitot tubes and static pressure probes for measuring the total and static pressure, respectively, as well as angle of attack probes and laser anemometer probes, called “LIDAR” probes, which send and receive laser radiation along one or more axes.
These probes are then connected to means for measuring and computing the corresponding property of the aircraft, such as its altitude, angle of attack, relative airspeed, etc.
The measurements are next grouped together and displayed on a screen of the Electronic Flight Instrument System (EFIS), which is a central information source from which the aircraft is piloted.
The angle of attack probes and pitot tubes assume the form of pallets and tubes protruding from the skin of the aircraft.
As a result, they are exposed to meteorological or mechanical factors that may alter their operation.
These factors, for example, comprise:                plugging of the probe orifices by dust or insects,        lightning strikes,        avian impacts during flight,        mechanical impacts occurring on the ground.        
As shown by the databases inventorying aeronautic incidents, these factors are a source of failures for protruding probes. These failures can result in erroneous measurements.
In order to offset these problems, the aeronautic certification rules require having redundant primary reference measurement means on the apparatus.
The commonly used solutions consist of having back-up probes, or combining a redundant probe with a pre-existing probe.
Thus, most aircraft whose cabins are not pressurized have a backup static pressure probe accessible from the flight deck and which can be triggered in case of failure.
Furthermore, multifunctional probes exist for example combining static and total pressure probes with a temperature probe.
However, these solutions are not fully satisfactory.
In fact, most of the existing redundant probes are of the protruding type and consequently have failure risks of the same nature as the probes that they are intended to back up.
Lastly, the combination of a probe with a pre-existing probe may require a new certification of the resulting probe if its geometry is altered.